Hi all! I did some searching around the forum and found Swamper77 posting the automata generators for passenger and freight trains. I remembered downloading a road automata generator a few years back, and I purged my plugin list to start over (in a vain effort to reorganize things).
So, I need to enlist your help to locate the road automata generator :) thank you guys so much!
Jeiman2008's Persistent Automata Mod (http://www.simtropolis.com/stex/details.cfm?id=23362) may be what you want.
I know that the latest NAM install has a few options for automata as well. Jeiman2008's will over ride it if you follow the instructions on the link page.